Exemplary embodiments of the invention relate to the art of electric machines and, more particularly, to a spool assembly for an electric machine.
Certain electric machines, such as claw-pole alternators, include a rotor formed from a plurality of steel segments, a steel core, magnet wire, and a spool assembly. The spool assembly includes a spool configured to insulate the magnet wire from the steel core, and flaps that are configured to insulate the magnet wire from the steel segments. Prior art spools were formed completely from plastic. The plastic spools were bulky which limited carrying capacity for the magnet wire.
Newer spool assemblies employ a plastic spool, indicated generally at 2 in FIG. 1, and laminate flaps (not shown) formed in a star. The laminate flaps or stars allowed for a spool assembly that was much thinner than the prior art plastic spool assemblies. The thinner design increased carrying capacity for the magnet wire and heat transfer from the spool assembly. While the newer spool assemblies have several advantages over the older completely plastic designs, a disadvantage exists in that the laminate flaps are attached to spool 2 by sonic welding. Not only is sonic welding a difficult and expensive process, sonic welding also requires that spool 2 include thick plastic portions in the form of opposing thick flanges 4 and 5 that provide weld support surfaces, one of which is indicated at 8. The thick plastic portions or thick flanges 4 and 5 defeat the purpose of the new design. That is, by adding thick flanges 4 and 5 to spool 2, magnet wire carrying capacity is reduced.